SMT设备原理与应用-_概述

SMT设备原理与应用PrincipleandApplicationofSMTEquipment,2010.9,本课程主要讲述内容，时间安排，考试安排，实验，辅导和平时考勤SMT工艺流程和相关设备,SMT设备概述Summarize,SMT概述与发展趋势4学时summaryandtrend焊膏组成与印刷的方式4学时solderpastecompositionandprintingtechnology印刷机原理与应用6学时principleandapplicationofprinter贴片机原理与设备12学时principleandapplicationofplacementmachines波峰焊原理与应用6学时principleandapplicationofwavesolderingoven再流炉原理与应用6学时principleandapplicationofreflowsolderingoven检测设备4学时inspectionequipment,本课程的主要内容Including,SMT生产线参观（印刷机、再流炉）2学时VisitingSMTproductionline(printer,reflowoven)贴片机编程原理；2学时Mounter(placementmachines)program贴片设计性实验。2学时Placementprocessdesignexperiment,实验内容experimentcontent,期末考试：开卷，占总分60%平时：20%（作业50%+考勤40%+特别贡献10%）实验：20%,考试方式testrules,联系方式indachuan2009，ldc2005辅导时间和地点：地点：时间：每周,辅导时间和联系方式,SMT概述与发展趋势,SummaryandTrends,Surfacemounttechnologywasdevelopedinthe1960sandbecamewidelyusedinthelate1980s.MuchofthepioneeringworkinthistechnologywasbyIBM.ComponentsweremechanicallyredesignedtohavesmallmetaltabsorendcapsthatcouldbedirectlysolderedtothesurfaceofthePCB.Componentsbecamemuchsmallerandcomponentplacementonbothsidesofaboardbecamefarmorecommonwithsurfacemountingthanthrough-holemounting,allowingmuchhighercircuitdensities.Surfacemountinglendsitselfwelltoahighdegreeofautomation,reducinglaborcostandgreatlyincreasingproductionrates.SMDscanbeone-quartertoone-tenththesizeandweight,andone-halftoone-quarterthecostofequivalentthrough-holeparts.,SMT技术发展历史和优点Historyandbenefits,常用术语Terms,ChipResistor,chipcapacitor,chipinductor,discretesemiconductor,SO,ChipCarrier,PlasticLeadlessChipCarrier,LeadlessCeramicChipCarrier,QuadFlatPackage,Ballgridarray,ThesolderjointcongurationsoftheICpackagescanberepresentedbyvemajorcategories,Gullwingleads翼型引脚,J-leaddesignJ型引脚,Butt-leads对接引脚,leadless,Ball-lead球形引脚,Typesofsurfacemountassemblytechnology,表面组装技术的类型,TypeIsurfacemountboardshaveSMCsonlyforbothsidesoftheboards,TypeIIboardshavebothSMCsandTHCsononesideoftheboardandchipcomponentsontheotherside,TypeIIISMThaveTHCsononesideoftheboardandchipcomponentsontheotherside,Surfacemountsolderingprocess,表面组装焊接类型,Wavesoldering,适用于通孔装配技术THT和通孔元件THC为了减小阴影效应（shadowingeffect）,通常采用双波峰技术（dualwave）,前面是湍流波（turbulentwave）用于确保所有的引脚润湿，后面的层流波（laminarwave）用于焊接波峰焊仅适用于小的SMCs，大的SMCs和行间距依然是存在桥接（bridge）和焊锡不足等问题,reflowsoldering,使用预配置好的焊膏（solderpaste）进行焊接，焊膏本身可以作为粘接剂焊膏用模版印刷到PCB上采用贴片机进行元件放置在回流炉（reflowoven）中多个温区进行整体加热焊接,reflowsoldering,solderpasteservesnotonlyasasoldermaterial,butalsoasaglue.thedepositionofsolderpasteisusuallyconductedbythestencilorscreenprinting,dispensing,orpin-transferringprocesses.Thepremetereddepositionofsoldermaterialontothesitestobesolderedensuresaconsistentsoldervolumeforthejoints,andaccordinglyeliminatestheinsufcientsoldervolumeproblemsduetotheshadowingeffectencounteredbywavesoldering.Inaddition,thispremeteredsolderdepositionalsoreducestheincidenceofbridging.,AdvantagesofsolderpastetechnologyinSMT,theuseofmassreowprocessallowsawell-controlledgraduateheatingprole,thuseliminatingpotentialdamageoftheSMCsduetothethermalshockcausedbythewavesolderingtheuseofsolderpasteallowsthepossibilityofstepsoldering.thesolderingperformanceofsolderpasteisnotsensitivetothetypeofsoldermaskusedonthePCBs.Forthewavesolderingprocess,asoldermaskwithasmoothnishisfoundtocausesolderballandbridgingproblems.,AdvantagesofsolderpastetechnologyinSMT,技术发展趋势,Surfacemounttechnologytrends,Technologydrivingforce,SmallerFasterHighercomplexityLowerpowerLowercost,Speed,processingspeedincreasesapproximatelyvetimesinevery5years;resultsfromreductioninbothon-chipdelayinsemiconductorsandpackagingdelaythisimprovementinspeediscloselyassociatedwithminiaturizationofICcomponents,asdemonstratedbythesimultaneousreductioninlinewidths,ICtransistorintegrationThecomplexityofsemiconductorchipscanbemeasuredbytransistorintegration.microprocessorintegrationhasincreasedby2000sinceitsintroductionin1970Thisincreaseincomplexityofsemiconductorchipsessentiallydrivestheevolutionofcorrespondingpackagingandassemblytechnology,Complexity,Pincountnumberthepincountnumberwillincreasealmost100fromthethrough-holetechnologyintheearly1980stomodules/systempackaginginthelate1990s.,Complexity,ICfeaturesizeDiscretecomponentsize,Miniaturization,Areaarraypackages,Pressureofspeed,complexity,andminiaturizationhavedriventheperipheralpackagedesigndownto0.3mm(16mil)pitchforQFP17therapidlyincreasingdefectrateassociatedwithminiaturizationofperipheraldesignwasrecognizedveryquicklyasthebottleneckinfurtherimprovementsinperformance.theassemblydefectrate(ppm)ofQFPisastrongfunctionofthepitchsize.Thedefectrateis25to40ppmfor50milpitch,andgraduallyincreasesto25to100ppmfor30milpitchand40to233ppm(5sigmacontrol)for25milpitch.Thedefectratebecomesprohibitivelyhigh,100to2300ppm,for20milpitch.Thishighdefectrateisprimarilyassociatedwiththevulnerabilityoftheslim,thingullwingleadsofQFPtowardhandling.Thehighprecisionrequiredfortheultra-ne-pitchcomponentplace